Any lawful building, structure or use of premises existing at the effective date of the original zoning law of the city, as approved by the Olean Common Council on July 28, 1936, or any subsequent amendment thereof applying to such building, structure, or use of premises, may be continued although such building, structure, or use of premises does not conform to the provisions of this law provided however:
12.0.1 
Nothing herein contained shall be construed to render lawful any use not lawfully conforming to provisions of the city's zoning law hereby repealed.
12.0.2 
Any extension of a non-conforming use must conform to the provisions of this law.
12.0.3 
No non-conforming building or structure shall be enlarged, extended or increased during its life to an extent exceeding 15% of its existing gross floor area or in aggregate value 50% of the replacement cost of the building, whichever is greater, unless said building or structure is changed to conform to the requirements of this law.
12.0.4 
A building or structure containing a non-conforming use may be repaired or strengthened sufficiently to remove a hazard to public safety, as such hazard may be determined by the code enforcement officer, but not so as to perpetuate the non-conforming use or character of the structure. Nothing in this law shall prevent the strengthening or restoring to a safe condition any wall, floor or roof which has been declared unsafe by the code enforcement officer.
12.0.5 
Only by approval of the zoning board of appeals shall a building used to house a non-conforming use be restored if damaged or destroyed by fire, flood, earthquake or other act of God. Substantial restoration shall be made within six months of the occurrence of the damage, except that this time limit may be extended by the zoning board of appeals in cases of practical difficulty or hardship. Any building damaged by such occurrence to the extent of more than 50% of its replacement value and not demolished shall be repaired or rebuilt within a six-month period to conform to the building line of the original structure.
12.0.6 
No non-conforming use shall be maintained, renewed, changed or extended without a certificate of compliance having first been issued by the code enforcement officer.
[L.L. No. 5-00, § 1, 9-26-2000]
12.1.1 
Any building or land which is used for or occupied by a non-conforming use and which is changed to or replaced by a conforming use, shall not thereafter be used for or occupied by a nonconforming use.
12.1.2 
When a non-conforming use has been discontinued for a period of one year, it shall be deemed abandoned and shall not thereafter be re-established and the future use shall be in conformity with the provisions of this law.
12.1.3 
Within residential districts, no off-street parking is required for a building that was last utilized for a nonconforming use regardless of how long the building or any portion of the building was vacant so long as the building (1) is being converted into a single or a two-family residential use, and (2) has no more than five bedrooms in the entire building. Within the meaning of this provision, the term "bedroom" includes any room with a bed and any room that is actually used for overnight sleeping, like a den.
A building or structure of non-conforming use may be repaired or restored to a safe condition except as specified in section 12.5.
Any building or structure for which a building permit was issued prior to the effective date of this law, or any subsequent amendment thereof applying, may be completed and used in accordance with the plans and specifications for such building and structure.
12.4.1 
Any lot held in single and separate ownership prior to the adoption of this law, and whose area is less than the specified minimum lot requirements of this law for the district, may be considered as complying with such minimum lot requirements and no variance shall be required, provided that:
1. 
Such lot does not adjoin any other lot or lots held by the same owner whose aggregate area is equal to or greater than the minimum lot area required for that district.
2. 
Such lot has an area of at least 3,000 square feet and a minimum width of at least 40 feet at the required setback line if it is to be used for residential purposes.
3. 
The following minimum yard dimensions are maintained for residences:
Side yards—Four feet.
Rear yards—Ten feet.
Front yards—Fifteen feet.
4. 
No detached accessory building shall be located closer to a side lot line than three feet, nor less than five feet to the residence building and is located behind the rear line of such residence building. No accessory building shall be located closer to the rear lot line than three feet if no easement is located along such rear lot line.
5. 
All other bulk requirements for that district are complied with.
12.4.2 
In any district where residences are permitted, such undersized non-conforming lots may be used for not more than one single-family dwelling.
A building permit shall not be issued for any lot that is reduced in area so that it creates a non-conforming bulk or use in violation of any regulations contained in this law.